Electrical equipment that is assembled or installed in the field, especially where the equipment is not a single unit, frequently requires interconnection by means of electrical conductors. Terminals are usually provided on the equipment package for receiving these conductors. Such terminals include various screw and post type devices where the conductor is wrapped around a screw and the screw tightened, the conductor is inserted into a hole and a screw is tightened onto the conductor, or other similar devices. Electrical circuitry is usually provided in the form of circuit boards which are somewhat delicate and do not lend themselves to screw type terminals for interconnecting wiring. Additionally, when a wire is terminated to a circuit board in one piece of equipment and then routed to another piece of equipment and terminated there, especially in a home environment, the wire is prone to inadvertent pulling by something falling against the wire or by someone accidently tripping over it. The wire may be inadvertently pulled completely out of the equipment or, if locked in place, may damage the delicate circuit board or other parts of the equipment. In an effort to reduce the work involved in the field when installing systems, a poke home terminal system was developed where the conductor is simply inserted into a hole in the unit and a spring contact inside makes electrical contact with the conductor. However, these systems are not suitable for interconnecting wiring to the circuit boards of electrical equipment where the wiring is exposed to such hazards. An example of such a terminal is disclosed in U.S. Pat. No. 3,915,544 which issued Oct. 28, 1975 to Yurtin. There, a spring terminal is disclosed that interconnects a conductor with circuitry on a flexible circuit that is arranged on the surface of a panel. A cavity is provided in the panel to receive the spring terminal in alignment with an opening in the flexible circuit. Conductive strips of the flexible circuit overlay the opening so that when the terminal is pushed into the cavity, the strips are deflected into the cavity and into electrical engagement with the terminal. Spring tabs deflect around the panel opening and snap into place behind the panel to hold the spring terminal in the cavity. A conductor to be terminated to the equipment is then inserted into a hole in the terminal to electrically engage a contact. This type of spring terminal does not lock the conductor in place within the terminal. Another type of poke home terminal system that is commonly used in household wall receptacles is disclosed in U.S. Pat. No. 3,671,925 which issued Jun. 20, 1972 to Drapkin. The '925 patent discloses a receptacle connector having an opening for receiving a conductive wire and a spring contact bar arranged adjacent the opening so that when a wire is inserted into the opening the contact electrically engages the conductor of the wire and securely locks it within the receptacle. Another hole is arranged adjacent the first hole for receiving a tool to deflect the contact away from the conductor for release thereof. The opposite side of the receptacle connector has suitable openings for receiving a plug having pin contacts that electrically engage contact surfaces that are part of the spring contact bar within the receptacle connector. However, this receptacle connector is not suitable to interconnect wires to the circuitry of circuit boards.
What is needed is a poke home type terminal system that mounts to a circuit board in electrical equipment for interconnecting the conductor of a wire to circuitry on the circuit board and locking the conductor in place. A release mechanism should be provided that releases the terminated conductor without overstressing the contact. Provision should be made for preventing damage to the equipment due to inadvertent pulling of the conductor in service.